/*
 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 *
 */

package java.sql;

import java.util.Iterator;
import java.util.NoSuchElementException;
import java.util.concurrent.atomic.AtomicReferenceFieldUpdater;

/**
 * <P>An exception that provides information on a database access
 * error or other errors.
 *
 * <P>Each <code>SQLException</code> provides several kinds of information:
 * <UL>
 * <LI> a string describing the error.  This is used as the Java Exception
 * message, available via the method <code>getMesasge</code>.
 * <LI> a "SQLstate" string, which follows either the XOPEN SQLstate conventions
 * or the SQL:2003 conventions.
 * The values of the SQLState string are described in the appropriate spec.
 * The <code>DatabaseMetaData</code> method <code>getSQLStateType</code>
 * can be used to discover whether the driver returns the XOPEN type or
 * the SQL:2003 type.
 * <LI> an integer error code that is specific to each vendor.  Normally this will
 * be the actual error code returned by the underlying database.
 * <LI> a chain to a next Exception.  This can be used to provide additional
 * error information.
 * <LI> the causal relationship, if any for this <code>SQLException</code>.
 * </UL>
 */
public class SQLException extends java.lang.Exception
    implements Iterable<Throwable> {

  /**
   * Constructs a <code>SQLException</code> object with a given
   * <code>reason</code>, <code>SQLState</code>  and
   * <code>vendorCode</code>.
   *
   * The <code>cause</code> is not initialized, and may subsequently be
   * initialized by a call to the
   * {@link Throwable#initCause(java.lang.Throwable)} method.
   * <p>
   *
   * @param reason a description of the exception
   * @param SQLState an XOPEN or SQL:2003 code identifying the exception
   * @param vendorCode a database vendor-specific exception code
   */
  public SQLException(String reason, String SQLState, int vendorCode) {
    super(reason);
    this.SQLState = SQLState;
    this.vendorCode = vendorCode;
    if (!(this instanceof SQLWarning)) {
      if (DriverManager.getLogWriter() != null) {
        DriverManager.println("SQLState(" + SQLState +
            ") vendor code(" + vendorCode + ")");
        printStackTrace(DriverManager.getLogWriter());
      }
    }
  }


  /**
   * Constructs a <code>SQLException</code> object with a given
   * <code>reason</code> and <code>SQLState</code>.
   *
   * The <code>cause</code> is not initialized, and may subsequently be
   * initialized by a call to the
   * {@link Throwable#initCause(java.lang.Throwable)} method. The vendor code
   * is initialized to 0.
   * <p>
   *
   * @param reason a description of the exception
   * @param SQLState an XOPEN or SQL:2003 code identifying the exception
   */
  public SQLException(String reason, String SQLState) {
    super(reason);
    this.SQLState = SQLState;
    this.vendorCode = 0;
    if (!(this instanceof SQLWarning)) {
      if (DriverManager.getLogWriter() != null) {
        printStackTrace(DriverManager.getLogWriter());
        DriverManager.println("SQLException: SQLState(" + SQLState + ")");
      }
    }
  }

  /**
   * Constructs a <code>SQLException</code> object with a given
   * <code>reason</code>. The  <code>SQLState</code>  is initialized to
   * <code>null</code> and the vendor code is initialized to 0.
   *
   * The <code>cause</code> is not initialized, and may subsequently be
   * initialized by a call to the
   * {@link Throwable#initCause(java.lang.Throwable)} method.
   * <p>
   *
   * @param reason a description of the exception
   */
  public SQLException(String reason) {
    super(reason);
    this.SQLState = null;
    this.vendorCode = 0;
    if (!(this instanceof SQLWarning)) {
      if (DriverManager.getLogWriter() != null) {
        printStackTrace(DriverManager.getLogWriter());
      }
    }
  }

  /**
   * Constructs a <code>SQLException</code> object.
   * The <code>reason</code>, <code>SQLState</code> are initialized
   * to <code>null</code> and the vendor code is initialized to 0.
   *
   * The <code>cause</code> is not initialized, and may subsequently be
   * initialized by a call to the
   * {@link Throwable#initCause(java.lang.Throwable)} method.
   */
  public SQLException() {
    super();
    this.SQLState = null;
    this.vendorCode = 0;
    if (!(this instanceof SQLWarning)) {
      if (DriverManager.getLogWriter() != null) {
        printStackTrace(DriverManager.getLogWriter());
      }
    }
  }

  /**
   * Constructs a <code>SQLException</code> object with a given
   * <code>cause</code>.
   * The <code>SQLState</code> is initialized
   * to <code>null</code> and the vendor code is initialized to 0.
   * The <code>reason</code>  is initialized to <code>null</code> if
   * <code>cause==null</code> or to <code>cause.toString()</code> if
   * <code>cause!=null</code>.
   * <p>
   *
   * @param cause the underlying reason for this <code>SQLException</code> (which is saved for later
   * retrieval by the <code>getCause()</code> method); may be null indicating the cause is
   * non-existent or unknown.
   * @since 1.6
   */
  public SQLException(Throwable cause) {
    super(cause);

    if (!(this instanceof SQLWarning)) {
      if (DriverManager.getLogWriter() != null) {
        printStackTrace(DriverManager.getLogWriter());
      }
    }
  }

  /**
   * Constructs a <code>SQLException</code> object with a given
   * <code>reason</code> and  <code>cause</code>.
   * The <code>SQLState</code> is  initialized to <code>null</code>
   * and the vendor code is initialized to 0.
   * <p>
   *
   * @param reason a description of the exception.
   * @param cause the underlying reason for this <code>SQLException</code> (which is saved for later
   * retrieval by the <code>getCause()</code> method); may be null indicating the cause is
   * non-existent or unknown.
   * @since 1.6
   */
  public SQLException(String reason, Throwable cause) {
    super(reason, cause);

    if (!(this instanceof SQLWarning)) {
      if (DriverManager.getLogWriter() != null) {
        printStackTrace(DriverManager.getLogWriter());
      }
    }
  }

  /**
   * Constructs a <code>SQLException</code> object with a given
   * <code>reason</code>, <code>SQLState</code> and  <code>cause</code>.
   * The vendor code is initialized to 0.
   * <p>
   *
   * @param reason a description of the exception.
   * @param sqlState an XOPEN or SQL:2003 code identifying the exception
   * @param cause the underlying reason for this <code>SQLException</code> (which is saved for later
   * retrieval by the <code>getCause()</code> method); may be null indicating the cause is
   * non-existent or unknown.
   * @since 1.6
   */
  public SQLException(String reason, String sqlState, Throwable cause) {
    super(reason, cause);

    this.SQLState = sqlState;
    this.vendorCode = 0;
    if (!(this instanceof SQLWarning)) {
      if (DriverManager.getLogWriter() != null) {
        printStackTrace(DriverManager.getLogWriter());
        DriverManager.println("SQLState(" + SQLState + ")");
      }
    }
  }

  /**
   * Constructs a <code>SQLException</code> object with a given
   * <code>reason</code>, <code>SQLState</code>, <code>vendorCode</code>
   * and  <code>cause</code>.
   * <p>
   *
   * @param reason a description of the exception
   * @param sqlState an XOPEN or SQL:2003 code identifying the exception
   * @param vendorCode a database vendor-specific exception code
   * @param cause the underlying reason for this <code>SQLException</code> (which is saved for later
   * retrieval by the <code>getCause()</code> method); may be null indicating the cause is
   * non-existent or unknown.
   * @since 1.6
   */
  public SQLException(String reason, String sqlState, int vendorCode, Throwable cause) {
    super(reason, cause);

    this.SQLState = sqlState;
    this.vendorCode = vendorCode;
    if (!(this instanceof SQLWarning)) {
      if (DriverManager.getLogWriter() != null) {
        DriverManager.println("SQLState(" + SQLState +
            ") vendor code(" + vendorCode + ")");
        printStackTrace(DriverManager.getLogWriter());
      }
    }
  }

  /**
   * Retrieves the SQLState for this <code>SQLException</code> object.
   *
   * @return the SQLState value
   */
  public String getSQLState() {
    return (SQLState);
  }

  /**
   * Retrieves the vendor-specific exception code
   * for this <code>SQLException</code> object.
   *
   * @return the vendor's error code
   */
  public int getErrorCode() {
    return (vendorCode);
  }

  /**
   * Retrieves the exception chained to this
   * <code>SQLException</code> object by setNextException(SQLException ex).
   *
   * @return the next <code>SQLException</code> object in the chain; <code>null</code> if there are
   * none
   * @see #setNextException
   */
  public SQLException getNextException() {
    return (next);
  }

  /**
   * Adds an <code>SQLException</code> object to the end of the chain.
   *
   * @param ex the new exception that will be added to the end of the <code>SQLException</code>
   * chain
   * @see #getNextException
   */
  public void setNextException(SQLException ex) {

    SQLException current = this;
    for (; ; ) {
      SQLException next = current.next;
      if (next != null) {
        current = next;
        continue;
      }

      if (nextUpdater.compareAndSet(current, null, ex)) {
        return;
      }
      current = current.next;
    }
  }

  /**
   * Returns an iterator over the chained SQLExceptions.  The iterator will
   * be used to iterate over each SQLException and its underlying cause
   * (if any).
   *
   * @return an iterator over the chained SQLExceptions and causes in the proper order
   * @since 1.6
   */
  public Iterator<Throwable> iterator() {

    return new Iterator<Throwable>() {

      SQLException firstException = SQLException.this;
      SQLException nextException = firstException.getNextException();
      Throwable cause = firstException.getCause();

      public boolean hasNext() {
        if (firstException != null || nextException != null || cause != null) {
          return true;
        }
        return false;
      }

      public Throwable next() {
        Throwable throwable = null;
        if (firstException != null) {
          throwable = firstException;
          firstException = null;
        } else if (cause != null) {
          throwable = cause;
          cause = cause.getCause();
        } else if (nextException != null) {
          throwable = nextException;
          cause = nextException.getCause();
          nextException = nextException.getNextException();
        } else {
          throw new NoSuchElementException();
        }
        return throwable;
      }

      public void remove() {
        throw new UnsupportedOperationException();
      }

    };

  }

  /**
   * @serial
   */
  private String SQLState;

  /**
   * @serial
   */
  private int vendorCode;

  /**
   * @serial
   */
  private volatile SQLException next;

  private static final AtomicReferenceFieldUpdater<SQLException, SQLException> nextUpdater =
      AtomicReferenceFieldUpdater.newUpdater(SQLException.class, SQLException.class, "next");

  private static final long serialVersionUID = 2135244094396331484L;
}
